Clean air is critical for many mechanical and electronics environments. For instance, internal combustion engines require the intake of clean air to mix with the fuel to produce the explosion within the piston chamber that provides motor power. Forced-air heating, ventilation, and air-conditioning (“HVAC”) systems need a ready supply of air that can be treated within the furnace or air conditioner before it is circulated to a home or work environment. Computers and small electronics devices produce a large amount of heat that must be dissipated by fan-driven air flows.
In order to maintain proper operation of such internal combustion engines, HVAC systems, computers and electronic devices, however, the intake air flow must be filtered in order to remove unwanted particulate materials to protect internal components from abrasion or corrosion, or HVAC-treated air from pollens and other allergens. Thus, a filter assembly is typically secured to the air intake region to reliably remove dirt, dust, pollen, animal dander, and other particulate materials from the air before it enters the intake region.
Filtering media of a number of different constructions are known within the industry. On the one hand, they may be prepared from a woven mesh like a window screen having apertures that allow the passage of air, while preventing the passage of the undesirable particulate materials. Such woven screens can be made from metal or polymeric materials. On the other hand, filtering media may be manufactured from substantially flexible non-woven fibrous pads of either natural or synthetic origin that are capable of entrapping particulate matter contained within the air-flow passing through the filtering media.
Such filtration products commonly comprise an assembly of the filtering media with a support structure surrounding its perimeter. Such support structure may entail a metal, plastic, wood, or cardboard frame or bracket. The frame or bracket provides necessary structural support for the flexible woven or non-woven filtering media. It also provides a convenient means for securing the filter assembly to the air intake region. The support frame of the filter assembly may be secured to the underlying device surrounding the air intake port by means of screws, clips, or other mechanical fasteners. For example, U.S. Pat. No. 6,793,715 issued to Sandberg et al. discloses magnetic straps for attaching a filter to a metal equipment housing.
Alternatively, a glue or adhesive may be used. U.S. Pat. No. 5,827,340 issued to Fiske illustrates the use of double-sided tape used to affix a filter media to the air intake region of an electronics component. See also, U.S. Pat. No. 6,276,426 issued to Polak.
Pressure-sensitive adhesive can also be pre-applied to one surface of the filter media with a removable liner, as illustrated in U.S. Pat. Nos. 3,458,130 issued to Jahlin; 3,521,630 issued to Westberg et al; 4,340,402 issued to Catron; and 6,800,106 issued to Cogar, Sr. et al.
However, such filter assemblies containing self-adhesive support frames require both a frame that must be secured to the filtering media, and the application of pressure-sensitive adhesive to the frame during the manufacturing process. On the other hand, such filter assemblies relying upon double-sided tape prompts the need for an installer to reliably secure the tape to the filter assembly frame before installing the filter device to the underlying device, which can be time consuming, and if not done properly can enable unfiltered air to pass through the crack between the filter assembly frame and underlying device to adversely impact the internal components. Of course, the use of mechanical fasteners or a filter assembly bracket requires precise drilling of holes in the air intake region substrate.
Some efforts have been made within the industry to manufacture filter assemblies without a support frame or bracket. Therefore, U.S. Pat. No. 6,171,354 issued to Johnson discloses a filter for an HVAC system air intake register comprising a piece of filter media to which a pressure-sensitive adhesive is applied across one entire face in a discontinuous pattern, such as multiple dots of adhesive. This discontinuous pattern allows the filter to be secured to the register, while permitting air to pass through the portions of the filter media not covered by the adhesive dots. See also, U.S. Pat. No. 6,419,729 issued to Duffy et al.
U.S. Pat. No. 5,912,369 issued to Reeves teaches a self-adhesive air filter for an electrical component made from a fibrous air filter pad coated on its one face with a special air-permeable, non-drying adhesive like Duro's “All-Purpose Spray Adhesive” composed of n-hexane, dimethyl ether, and acetone). Such a special adhesive is required to offer minimal air flow resistance to the filter media, while releasably securing the air filter to the air intake region of the underlying device.
U.S. Pat. No. 4,600,420 issued to Wydeven et al. illustrates a HEPA filter for a computer disk drive comprising a mesh overlaid on top of the HEPA media. A latex resin is selectively applied to both sides of the non-filtering region of the mesh to fill the voids in the mesh to form a structural support. However, an adhesive ring with a release liner must be separately applied to one face of this latex resin structural support, so that the filter assembly can be secured to the underlying computer cabinet.
While such filter assemblies previously known within the industry may be capable of being affixed to an underlying device, they all require a support frame having pressure-sensitive adhesive or double-sided tape applied thereto, or special air-permeable adhesive or adhesives applied in discontinuous patterns to the entire face of a filter media lacking a support frame. It would therefore be advantageous to provide a filter assembly without a support frame containing an integral support structure that simultaneously supplies the adhesive properties uniformly across the integral support structure for conveniently securing the filter assembly to the underlying device.